Stormwater biofiltration system and method

ABSTRACT

A stormwater treatment system and method for removing sediment, chemical pollutants, and debris from stormwater runoff by utilizing bioretention practices including physical, chemical and biological processes. Stormwater is directed into a primarily open-bottomed, multi-dimensional container whereby entrained sediment and other transportable materials are filtered and treated through a media filter layer consisting of inorganic and/or organic materials. A live plant (preferably a tree) situated within the container with roots resident in the media filter layer with the ability for expansion beyond the perimeter of the container through openings in one or more sidewalls. The treated water may be further conveyed beyond the perimeter of the container by additional openings and/or piping. A vertically positioned overflow/bypass/clean out piping apparatus may be included within the stormwater treatment system to provide additional water conveyance. Additional ancillary conveyance, filtration and storage facilities may be connected to the described stormwater treatment system as conditions warrant.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation under 35 U.S.C. § 111(a) of U.S.patent applicant Ser. No. 15/735,940 filed on Dec. 12, 2017 (now U.S.Pat. No. 10,563,392) which is a continuation under 35 U.S.C. § 371 ofInternational Application No. PCT/US2016/046438 filed on Aug. 10, 2016,which claims priority to and the benefit of U.S. Provisional PatentApplication No. 62/203,618 filed Aug. 11, 2015, U.S. Provisional PatentApplication No. 62/253,752, which was filed on Nov. 11, 2015, and U.S.Provisional Patent Application No. 62/314,622 filed Mar. 29, 2016, theentire contents of each are incorporated by reference herein.

FIELD OF THE INVENTION

The application relates to a filtration system, method, and device tomanage and improve the quality of stormwater runoff by removing andremediating pollutant constituents entrained in the water by way ofphysical, chemical, and biological processes. The invention is intendedto collect and process stormwater emanating from paved and unpavedsurfaces, underground utilities, as well as from building roof drainstructures.

BACKGROUND OF THE INVENTION

Stormwater runoff transports varying quantities of pollutants such asoil/grease, phosphorous, nitrogen, bacteria, heavy metals, pesticides,sediments, and other inorganic and organic constituents with thepotential to impair surficial water bodies, infiltrate groundwater andimpact aquifer systems. The systemic sources of these pollutants arereferred to as either ‘point’ or ‘nonpoint’ (sources). Point sourcepollution is typically associated with a release such as a spill, or“end of pipe” release from a chemical plant. These are consideredreleases that can be tracked to a single location. Nonpoint sourcepollution is not readily discernible with respect to a single location,but is associated with combined pollutant loading and deposition frommany sources spread out over a large area including a variety of humanactivities on land (e.g., excess fertilizer runoff), vehicle emissions(e.g., oil, grease, antifreeze), vehicle material wear (e.g., brakepads, metal on metal rubbing, corrosion), as well as naturalcharacteristics of the soil and erosion, climate, and topography.Sediment transport is the most common form of nonpoint source pollutionas it can contain a myriad of soluble and insoluble pollutants,comingled and concentrated and easily transported over impervious andpervious surfaces. Nonpoint source pollution via stormwater runoff isconsidered to be the primary contributing factor in water degradation.Over the past three decades, many studies have been performed toidentify the major pollutant constituents typically found in stormwater,and their relative concentrations found in both urban and suburbanrunoff. Studies have consistently concluded that pollutant levels,particularly in urban runoff, contain concentrations of nutrients andother pollutants, with the potential to significantly impact receivingwaters such as streams, lakes, rivers, as well as our undergroundgroundwater aquifer system.

Pollutants in both soluble and insoluble forms such as nitrogen,phosphorous, zinc, copper, petroleum hydrocarbons, and pesticides atvarious concentrations are commonly found in the stormwater profile.These constituents maintain varying degrees of solubility and transportwith some being more mobile than others. Some constituents have achemical affinity to “sorb” (adsorb/absorb) and collect, or, “hitch aride,” onto sand particles, sediment, or other non-aqueous matterentrained in the stormwater during transport, thereby increasing themass of concentration. Sediment laden pollution can also impairwaterways due to increased levels of turbidity thereby decreasingsunlight penetration within water bodies, and impairing aquatic life.

Historically, stormwater management systems have relied on collectionand conveyance via a network of catchments and underground piping thattypically transfer and discharge stormwater to a downgradient waterbody. Additionally, the practice of stormwater detention and/orretention which relies on the collection or transfer of stormwater tosurficial ponds or holding areas whereby infiltration takes place, hasbeen a preferred management technique. Both of these managementtechniques are commonly referred to as “centralized” techniques whichwere designed primarily to move stormwater from paved areas, withoutconsideration of the pollutant loading effect.

Beginning in the early 1980's, academia, municipalities, state andfederal environmental regulatory agencies began looking at ways to bestmitigate problems associated with nonpoint source pollution andstormwater runoff. Instead of relying solely on centralized stormwatercollection and conveyance, a more “decentralized” approach to stormwatermanagement began to evolve. Such traditional physical factors indetermining stormwater control practices as site topography, soilpercolation rates, and degree of impervious cover were integrated withstrategic land planning in an attempt to best replicate pre-developmentconditions and preserve the natural process of direct subsurfaceinfiltration of precipitation. The focus turned to ways in whichinnovative engineering, and systems design and construction practices innew development and redevelopment could best be employed to reduce theimpact from increasing the impervious “footprint” thereby minimizingsite impact. The term “best management practices” (BMPs) was used tocollectively identify various stormwater control practices andmethodologies to achieve decentralized versus centralized management bytreating water at its source, instead of at the end of the pipe.

Low impact development (LID) is a term used to describe a land planning,engineering, and building design approach to managing stormwater runoff.LID emphasizes conservation and use of on-site natural features toprotect water quality. This approach implements engineered small-scalehydrologic controls to replicate or mimic the pre-development hydrologicregime of watersheds through infiltrating, filtering, storing,evaporating, and detaining runoff close to its source. The LID conceptbegan in Prince George's County, Md. around 1990 by municipal officialsas an alternative to traditional centralized control measures. Theseofficials found that traditional practices of detention and retentionand associated maintenance were not cost-effective, and in many cases,did not meet stormwater management goals, particularly with respect towater quality goals.

Today, LID stormwater management practices have shown in many cases toreduce development costs through the reduction or elimination ofconventional storm water conveyance and collection systems andinfrastructure. Furthermore, LID systems may reduce the need for paving,curb and gutter fixtures, piping, inlet structures, and storm waterponds by treating water at its source instead of at the end of the pipe.Although up-front costs for LID practices can be higher than traditionalcontrols, developers often recoup these expenditures in the form ofenhanced community marketability, and higher lot yields. Developers arenot the only parties to benefit from the use of LID storm watermanagement techniques, municipalities also benefit in the long termthrough reduced maintenance costs.

Of particular interest in regard to the present invention is a BMPpractice based on the principals of “bioretention.” Bioretention istypically defined as the filtering of stormwater runoff through aplant/soil complex to capture, remove, and cycle pollutants by a varietyof physical, chemical, and biological processes. Bioretention is apractice that relies on gravity to allow stormwater to infiltratethrough natural soil or engineered filter “media” complexes whileproviding some degree of sediment collection/separation, and encouragingmicrobial degradation of entrained pollutants. Such bioretentionpractices as “rain gardens” and “sand filters” which rely oninfiltration and natural pollutant attenuation began to be incorporatedas part of LID practices beginning in the 1990's. In these systems, theability and rate of water movement is not based upon structuralcontrols, but more a function of the composition of the media and/orsoils and the infiltration capacity. Although sand filters provide somedegree of bioretention efficacy, more importantly, rain gardens rely onplant systems to further enhance microbial activity, and assimilate anduptake pollutant constituents such as phosphorous, nitrogen, and variousmetals in their soluble form. Accumulated test data of pollutant removalrates for bioretention practices have consistency shown high levels ofcontrol and attenuation. Federal and state environmental protectionagencies recognize infiltration practices as the preferred means forreturning rainwater runoff to the natural aquifer system, as opposed topiping and discharging collected stormwater to a downgradient water bodylocation such as a river, lake, or the ocean.

Within the past decade, another BMP practice/system which relies oninfiltration and bioretention to achieve pollutant removal goals hasemerged. This system typically integrates a landscape tree or otherplant material with stormwater collection and remediation through anengineered filter media. The system is commonly referred to as a “treebox filter” system. The University of New Hampshire Stormwater Center(UNHSC) was one of the earliest institutions to construct and test atree box filter system. In 2007, UNHSC installed a tree box filtersystem at their campus test center. The system as designed was anapproximately six-foot diameter, three-foot deep, round concrete vaultresembling a large inverted concrete pipe. It was filled with abioretention soil mix composed of approximately 80 percent sand and 20percent compost. It was underlain horizontally by a perforated“underdrain” pipe at the base of the vault that was connected to, anddischarged infiltrated stormwater to an existing stormwater drainagesystem.

The system also contained an open-topped, vertical bypass pipe near thesurface to accommodate heavy stormwater events which would otherwiseoverwhelm the concrete vault. The vault was open-bottomed to providesome direct infiltration to the underlying soils. The filter media wasapproximately three feet deep and was designed to maximize permeabilitywhile providing organic content by the incorporation of compost andnative soils to sustain the tree. The vault was designed to beintegrated with a street curb opening to collect surface runoff. Duringa rain event, stormwater migrating along a street curb would enter thecurb cut opening and the vault system. The water then infiltratedthrough the media and was primarily conveyed through the sub drain pipeto the existing (separate) stormwater drainage system. Although thedevice had the capability of infiltrating stormwater to the surroundingenvironment through the open bottom, it principally relied on the subdrain pipe to convey stormwater to the existing drainage system.

Most recently, several proprietary tree box filter systems, and otherstructural bioretention systems, have been introduced for commercial useand are currently marketed as stormwater treatment devices for thecollection, filtration, and discharge of (treated) stormwater. As withthe previously described UNHSC system, these systems are primarily vaultsystems with enclosed walls. They typically are constructed as a waterimpermeable precast concrete container with four side walls with aperforated horizontal underdrain pipe located at the base of thecontainer. However, in contrast to the aforementioned UNHSC designsystem, these proprietary systems typically have a water impermeablebottom wall essentially forming a five-sided container, with a partiallyopen top sidewall to allow for plant growth. They are designed to beintegrated with street curbside collection with stormwater entering thesystem via an opening (throat) on one side of the container. Thecontainer typically contains a filter media of specific composition,with an overlying organic mulch media layer. The drain pipe collects andconveys filtered stormwater to an outlet point exterior of the containerthat is typically connected to a downgradient catch basin or otherexisting stormwater drainage system structure. The drain pipe istypically embedded in a layer of stone to facilitate collection andtransport of all infiltrating water to the outlet point. The collectionand treatment capacity of these close sided systems are defined by thehorizontal and vertical interior dimensions of the container. Plantmaterial is resident in the container with root growth confined withinthe container. These systems are designed to collect and infiltratestormwater emanating from aboveground surfaces, underground stormdrains, and building roof runoff. Based on third party evaluation andtesting data, these systems have proven to provide effective stormwaterquality treatment with the capacity to provide substantial pollutantremoval rates.

Although tree box filters and other closed box systems have proven to bean effective pollutant removal technology, several perceiveddeficiencies to their long term efficacy have been identified, which arethe inspiration and basis of the present invention.

Since tree box filter systems are inherently closed systems, both thefilter media and plant root systems are contained within a five-sidedbox, therefore, their identifying name. Not unlike a “pot bound” pottedplant, the roots of the plant (particularly trees) within a tree boxfilter are confined and restricted from normally developing and freelymigrating beyond the walls of the container.

It is common knowledge that the majority of tree root growth is in ahorizontal versus vertical direction. Roots primarily grow and spreadlaterally outward, and away from the tree trunk in search of nourishmentto include water, nutrients and oxygen. Based on documented studies andan accepted understanding of tree root growth by the arboriculture andhorticulture community, as well as an evaluation of tree root systemsfollowing disturbance or “wind throw”, as much as 80% of a mature tree'sroot system typically resides in the top 12 inches of soil. Therefore, atree's root mass exists, and growth takes place, within a shallowhorizontal matrix. It is also understood that a tree's roots normallygrow to and beyond the distance of its canopy, or outer perimeter ofleaf growth, typically by a factor of two or three times the distancebetween the trunk and outer edge of the canopy. Therefore, a healthy andthriving tree would require an extensive and unobstructed horizontaldimension to develop properly.

A majority of commercial proprietary tree box system containersencompass less than 40 square feet in horizontal dimension. Due to theaforementioned discussion of root growth requirements, an activelygrowing containerized tree, as typified by a tree box system, would beexpected to “outgrow” its horizontal dimension prior to attainingmaturity. The negative consequences from the exhaustion of growing area,and the adverse effects of restricting a tree's root system fromexpanding normally could be the stunting of growth, decline in health,and potential susceptibility to disease and insect infestation.Furthermore, actively growing roots will be deflected in opposingdirections following contact with an impenetrable obstacle such as thewall(s) of a tree box container. These roots have the potential toencircle the tree's trunk causing a condition called “girdling” wherebythe encircling roots can strangle the tree's trunk as well as otherdeveloping roots, choking off nourishment. These debilitating factorscould potentially lead to the premature death of the tree. If the treein a tree box system requires removal and replacement due to decline orpremature death, significant labor and material costs would be incurred.To facilitate tree removal, presumably most, if not all of the mediawithin the container would also require removal. This associated costand labor burden could further be exacerbated due to the potential needto remove existing stone surrounding the aforementioned underdrainpiping at the base of the container of the typical tree box filtersystem.

Another perceived deficiency due to the effect of the “consumption” ofmedia space by the ever increasing mass of root growth within theconfined space of a tree box system would be the eventual reduction ofstormwater movement and infiltration through the media filter. Mostcommercial tree box filter systems depend on rapid stormwaterinfiltration through the media to achieve treatment goals. The typicaltree box filter media is purposely engineered to be of a highly porousopen structure composition, primarily consisting of larger particlegravelly sands, thus providing rapid infiltration, as opposed to commonlandscape or garden soils that typically contain finer particles ofsands, silts, and clay that inhibit rapid infiltration. A lesserpercentage of the media mix is typically made up of these latterconstituents as well as organic materials such as peat moss or compostthat have the ability to absorb and retain water. These constituents arecritical in providing irrigation for the tree and to sustain rootgrowth, as well as promoting microbial growth for the degradation ofsome pollutants. However, it is apparent that the ever expanding networkof roots of a maturing tree confined within a tree box would be expected(in time) to interfere with and slow down the infiltration ofstormwater, thus reducing operational efficiency of the system.

An additional perceived deficiency with a conventional commercial treebox filter is that since these systems are primarily closed bottomed,the only means to discharge infiltrated stormwater outside of the treebox is by way of the underdrain pipe. Since this pipe is typicallyconnected to a downgradient catch basin, or other closed stormwatermanagement system, there is little opportunity to directly infiltratequantities of this filtered water to surrounding soils and thegroundwater system. If the surrounding soils are sufficiently permeable,as previously explained, direct infiltration is the preferred mode forreturning rain water, in the form of treated stormwater, to thegroundwater system. Therefore, an open bottomed tree filter system couldallow quantities of filtered stormwater to be returned to surroundingsubsurface soils and ultimately the groundwater system. Additionally,commercial tree box filter systems typically utilize a four or six-inchdiameter drain pipe as the sole means to discharge filtered water fromthe system container. The quantity of water, and speed for which watercould be evacuated from the container, are therefore severely limiteddue to the use of a small diameter outlet pipe as opposed to an openbottomed system such as the present invention.

As previously discussed, tree box filter systems (and other enclosedbioretention based structures) rely on an engineered media of highporosity that allows for the rapid infiltration of stormwater that isentering the system. These medias are composed of inorganic materials toallow for rapid infiltration, and organic materials which retain waterwithin the media to provide irrigation for the plant material. When bothinorganic and organic constituents are blended in correct proportions,the resulting engineered media provides a proper balance of highinfiltration capacity coupled with sufficient water holding capacity.

Recent studies have determined that the incorporation of specificmanufactured products or reconstituted rock-based materials formed byexpanding specific minerals under intense heat, often referred to as“ceramics”, into an engineered media that has the capacity to adsorband/or absorb (sorption) nutrients commonly found in stormwater runoff.Excessive concentrations of specific nutrients such as nitrogen,phosphorus, and soluble metals are known to pollute soils and waterbodies. Sorption occurs as a chemical or physical bonding process wherenutrients become “attached” to a material as it passes in aqueoussolution. Manufactured products such as activated aluminum and activatediron have shown a great affinity for the sorption of soluble phosphorusand other minerals in the aqueous stage. The incorporation of thesematerials in an engineered media have shown to provide a measurablereduction in soluble phosphorus in stormwater runoff influent. Ceramicssuch as expanded shale and expanded clay have also shown a propensityfor adsorbing minerals such as phosphorus and nitrogen. The mechanismfor this sorption reaction is due mainly in part to the presence of tinyholes and fissures within the lattice of the ceramic structure. Theseholes and fissures are the result of the artificially induced intenseheating of the expanded rock during the manufacturing process thatcauses the material to “pop”, forming these openings.

Water treatment plant processes employ manufactured products such ascoagulants to remove inorganic and organic matter suspended in theuntreated source water. Coagulants have the ability to bind smallcontaminant particles that are suspended in water which otherwise wouldavoid initial treatment. Water Treatment Residuals (WTRs) are theproducts produced following this coagulation process and treatmentprocess. This resulting product may be a thickened liquid or a dewateredsolid. In the solid form, these coagulant residual materials may beeither aluminum or iron based oxides and are known to have a strongcapacity to retain soluble phosphorus. It has been determined thataluminum and iron based WTRs, when exposed to stormwater influent, cancontinue to capture and retain over 90% of soluble phosphorus, evenafter several years of continued contact.

Incorporating any of these manufactured products including,reconstituted rock, and/or WTRs at no greater than 20% (±5%) by volumewith a high infiltrating engineered media achieving an infiltrationcapacity of greater than 50 (±5%) inches per hours would be expected toprovide a pollutant removal benefit in systems such as the presentinvention.

Manufactured tree box filter systems and other enclosed bioretentionbased structures are currently being used in many parts of the countryin both commercial and residential applications where a stormwatermanagement system is essential to mitigate nonpoint source pollution.These systems are typically manufactured of precast concrete by concretemanufacturers or their affiliates. They are customarily deliveredpre-filled with filter media and arrive at a site ready for installationand the incorporation of the final plant product. The primary intent ofa closed box system design prefilled with media is to be one of a“packaged” and “drop in place” product, uniform in construction, therebyexpediting installation and reducing handling time and associated costs.Essentially closed-bottomed and closed-sided pre-cast concrete waterimpermeable treatment containers are described in U.S. Pat. Nos.8,333,885, 6,277,274, 6,569,321, and 8,771,515.

Several advantages to the present invention as to be detailed in thefollowing description are designed to rectify the perceived deficienciesin current tree box filter systems, as well as provide additionalbenefit. Some of these advantages include, an open sided and openbottomed design to allow for direct infiltration; incorporating anengineered media amended with a manufactured product(s) or reconstitutedrock-based materials to provide greater nutrient pollutant removalefficacy; the ability to service street, and building roof runoff; allowfor multiple subsurface pipe openings; and, the ability to use aflexible, impermeable or substantially impermeable subsurface liner toprovide an enclosed treatment area. These, and other advantages willbecome apparent from a consideration of the following description andaccompanying drawings.

BRIEF SUMMARY OF THE INVENTION

The present invention is intended to be a stormwater treatment systemwith bioretention functionality and is designed to treat stormwaterrunoff emanating from either pervious or impervious surfaces (e.g.,streets, parking lots, grassed areas, rooftops). An embodiment consistsof a primarily open-bottomed container with a top sidewall at leastpartially open to the atmosphere, and side walls of varying verticaldimension. The container contains a filter media consisting of a mixtureof organic and non-organic materials. Portions of the filter media onone or more sides of the container may maintain contact or otherwisecommunicate with the surrounding native or existing soil. Plant materialwill be located within the container with vegetative growth emanatingthrough a central opening(s) in the top sidewall portion of thecontainer, with at least partial, or free expression of the attendedroot system beyond the exterior “footprint” of the container.

This and other embodiments and features of the present invention willbecome apparent from the following detailed description, accompanyingillustrative drawings, and appended claims.

DEFINITIONS

The following terms are defined to aid the reader in fully understandingthe operation, function, and utility of the present invention.

“Accumulating stormwater” as used herein, refers to conditions when thesystem is inundated with a large volume of stormwater due to a severestorm, such as a hurricane, or a long and/or intense period of rain.

“Affixed” as used herein, refers to the possibility that one or morethings may be connected, by a variety of means, including, but notlimited to a fastening device, such as a hinge, bolt, screw, rebar orthe like, and adhesive, such as an epoxy, or a preformed interlockinggroove or cutout. Affixed also takes into consideration joining twoparts during the manufacturing process wherein the two claimed parts aremanufactured as one complete part.

“And/or” as used herein, refers to the possibility that both items orone or the other are claimed. For instance, A and/or B refers to thepossibility of A only, B only or both A and B are present in the claimedinvention.

“Aggregate media” as used herein, refers to a sum, mass, or assemblageof various loose particles of inorganic and/or organic matter.

“Base” refers to the bottom or lowest part of something; the part onwhich something rests or is supported.

“Bioretention functionality” as used herein, refers to the functioningprocess in which nutrients, contaminants and aggregate media particlesare removed from stormwater runoff through a combination of physical,chemical and biological processes as the water infiltrates and passesthrough the media layers within the stormwater treatment system.

“Clean out access pipe” as used herein, refers to that pipe which iswithin the container and is positioned in a vertical orientation andconnected to the horizontally positioned underdrain pipe. This pipe mayalso serve the dual purpose as the overflow/bypass pipe which evacuatesaccumulated water within the container which cannot otherwise infiltratethrough the layer(s) of inorganic and/or organic materials of thestormwater treatment system.

“Dimensional stone” as used herein, refers to a stone or rock of aspecific size and shape.

“Discrete layer” as used herein, refers to an individual layer which isseparate and different from any and all other layers.

“Elevation” refers to a geographic location and its height above orbelow a fixed reference point. That which is a “raised elevation” risesabove its surrounding elevation.

“Filtering media” as used herein, refers to those layers either discreteor in combination of inorganic and/or organic material which have beenintroduced to and are resident within the container, and potentiallyexterior of the container. The filtering media allows for theinfiltration and flow thru of incoming stormwater and is designed toprovide treatment for nutrients and contaminants entrained in the water.

“Fittings” as used herein, refer to those fixtures and furnishings usedto connect and interconnect plastic pipe in combination with plumbingand drain systems allowing for multi directional positioning bothvertically and horizontal. Fittings could include, but are not limited,to such items as known in the commercial trade as valves, elbows, tees,wyes, and unions, and the like.

“Geotextile fabric material” as used herein, refers to permeable fabricswhich have the ability to separate and maintain segregation between twodiscrete layers of inorganic or organic materials while still allowingfor the infiltration of water between the two layers. Geotextile fabricsare typically constructed of fiberglass, polypropylene, polyester, orthe like.

“Impermeable material” as used herein, refers to those materials whethernatural or synthetic which restrict a thing or force from penetratingsaid material. Impermeability is the resistance to that potentialpenetration.

“Impervious subsurface membrane liner” as used herein, refers to asynthetic, flexible material which acts as a barrier to separate andmaintain segregation between two discrete layers of inorganic and/ororganic materials thus preventing the infiltration of water between thetwo layers.

“In contact with” as used herein, refers to conditions when an actionwith one element causes a secondary action in a second element. Forinstance, when two pipes are “in contact with” each other, stormwatermay flow from one pipe to a second pipe when said pipes are “in contactwith” each other.

“Interior” refers to the space created when all sidewalls are affixed toeach other.

“Inorganic material” refers to matter which is not derived from livingorganisms and contains no organically produced carbon. It includesrocks, minerals and metals. Inorganic matter can be formally definedwith reference to what they are not: organic compounds.

“Manifold pipes” refers to a combination of one or more smaller pipes orchannels which lead out from a bigger pipe, typically in a perpendicularradius from the bigger pipe. A manifold is a component that is used toregulate fluid flow in a hydraulic system, thus controlling the transferof water.

“Open public area” refers to those areas that are open for public accessand use. These areas may be owned by a national or local governmentbody, ‘public’ body (e.g. a not-for-profit organization) and held intrust for the public, or owned by a private individual or organizationbut made available for public use or available public access

“Organic material” refers to matter that was once alive and is invarious states of decomposition. Dead plants, animals, bacteria andfungi are all examples of organic material.

“Overflow or internal bypass conduit” as used herein, refers to avertical pipe and passage by which to evacuate and convey excess stormwater that enters the container and then rises above the surface of themedia and otherwise inundate the container. This condition typicallyarises when the rate and volume of water entering the container isgreater than the ability of the media to infiltrate and transfer thewater.

“Partial horizontal top sidewall” as used herein, refers to the topportion of the container, either separate or affixed to the container,which is at least partially open to the surrounding environment.

“Receiving facility” as used herein, refers to those structures or landmasses either natural or man-made which receive incoming stormwater fromanother so defined facility.

“Separating layer” as used herein, refers to an individual layer whichis separate and different in characteristics and/or properties from thatof the overlying and underlying layers.

“Stormwater” refers to water that originates during precipitation eventsand snow/ice melt. Stormwater can soak into the soil (infiltrate), beheld on the surface and evaporate, or runoff and end up in nearbystreams, rivers, or other water bodies (surface water).

“Stormwater receiving receptor” as used herein, refers to those bodiesof land or water which receive stormwater from an upgradient locationassociated with the stormwater management system of the presentinvention. The receptor may be sensitive to and/or otherwise impacted bythe receiving waters and potential contaminant load.

“Stormwater treatment system” as used herein, refers to the interior andexterior components of the present invention.

“Straight line pipes” as used herein, refers to those pipes thattraverse or travel across a surface in one continuous direction.

“Vertical sidewall” as used herein, refers to one of four sides thatform the vertical dimension of the container.

“Watertight” refers to a material or thing that is closely sealed,fastened, or fitted so that no water enters or passes through it.

“Water treatment residual” refers to the waste by-product that isproduced as part of water treatment processes to remove contaminants.These residuals form when suspended solids in the target water reactwith chemicals (e.g., coagulants) added in the treatment processes andassociated process control chemicals (e.g., lime). These residuals havethe ability to adsorb or otherwise attract and bind nutrients such asphosphorus to its surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cutaway perspective view of various aspects of a stormwatertreatment system of the present invention.

FIG. 2 is a cutaway cross-sectional view of the first embodiment of thestormwater management system of the present invention with internalcollection and discharge piping.

FIGS. 3(a), 3(b), and 3(c) is a cutaway perspective view, plan view, andcutaway perspective view, respectively, of a second embodiment of astormwater management system of the present invention.

FIG. 4 is a cutaway perspective view of a third embodiment of astormwater management system of the present invention with a separatetop slab.

FIGS. 5(a) and 5(b) is a cutaway cross-sectional view, and plan view,respectively, of a fourth embodiment of inflow and outflow pipes andopenings of a stormwater management system of the present invention.

FIG. 6 is a cutaway cross-sectional view of a fifth embodiment of astormwater management system of the present invention.

FIGS. 7(a) and 7(b) is a cutaway perspective view, and plan view,respectively, of a sixth embodiment of a stormwater management system ofthe present invention.

These renderings are included for illustrative and interpretive purposesrelative to specific embodiments and applications and should not beconstrued as the sole positioning, configurations, or singular use ofthe present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention is designed to be a stormwater management systemwhereby stormwater combined with mixed debris, sands, sediment,entrained and dissolved chemical and biological pollutants areseparated, treated and/or remediated via physical, chemical, andbiological processes prior to being infiltrated to the subsurfaceenvironment, and/or discharged to a separate drainage system. Referringnow to the drawings, and specifically to FIG. 1, the present inventionis comprised of a substantially water impermeable open bottomedcontainer 1 of various dimensions and configurations with an open bottomand vertical sidewalls 10, 11, 12, 13, of various height and enclosure,and horizontal (top) sidewall 2 at least partially open to theenvironment. The container contains a mixture and/or discreet layer(s)of both organic and inorganic materials (media) 6 which may or may notextend beyond the outside perimeter of the container. The containermaintains vegetative plant(s) 5 whose roots 8 are resident in the mediaand are able to communicate unrestricted with the surrounding nativesoils or introduced soils 9.

While continuing to reference FIG. 1, and also FIG. 2, the followingdescription includes the preferred embodiment, manner of operation, andpollutant removal function(s). Stormwater enters the substantially waterimpermeable open-bottomed container 1 through one or more openingslocated on the container or through an opening 3 on a sidewall thatabuts a street or impervious surface 4 with associated curbing 7. Thepreferred embodiment of the container is of a water tight concrete,metal, or plastic (or other impermeable substance) fabrication. Theconfiguration, horizontal dimensions and shape of this container isprimarily determined based on site logistics, and the size of theappropriate media dimensions to accommodate the flow emanating from thecontribution area that makes up the incoming stormwater flow.

Incoming stormwater flows immediately into the container 1, quantitiesof sand, sediment, and other floatable or non-floatable matter entrainedwithin the stormwater flow also enters the container and accumulate onthe surface of the media 6.

As the water infiltrates through the media, additional quantities ofsands and sediment may either become resident in the media or continueentrained with the water flow. Additionally, organic nutrients such asnitrogen and phosphorus, amongst others, and metals such as zinc andcopper, amongst others, within the stormwater flow may adhere to theaggregate media and/or continue to pass through the media. The media iscomprised of a mixture of aggregates (e.g., sand, gravel, stone), andorganics, to achieve a substantial rate of infiltration, whilemaintaining moisture holding capacity to maintain biological activityand support plant growth. An embodiment would be the incorporation of anadditive in the aggregate media that would contain an iron or aluminumoxide product, an expanded ceramic, and/or a water treatment residual ofno greater than 20% (±5%) by volume to enhance the nutrient removalpotential of the non-amended media.

The water infiltrates through, and then exits the media layer of thecontainer. The infiltrating water than typically communicates with anunderlying layer of stone or other aggregate 14. A preferred embodimentwould be a “separating” layer 19 consisting of either or both amanufactured geotextile fabric material, and a dimensional stonediffering from that of the aforementioned underlying layer ofstone/aggregate. The base of the container is envisioned to either reston top of this stone/aggregate layer, or be partially embedded withinthis layer. It is envisioned that native soils or introduced soils 9would be resident below this layer of stone. Depending upon theinfiltration capacity of these soils, water would be allowed to freelymigrate and/or infiltrate both vertically and horizontally. A preferredembodiment would be that an underdrain pipe 15 is provided adjacent tothe bottom of the container within the stone layer 14 having a pluralityof openings 16 that receive the infiltrating stormwater as it flowsthrough the overlying media. This stormwater may then be transferredoutside the footprint of the container and directed to another receivingfacility. Associated with the underdrain pipe is a vertical pipe 17which serves as either a cleanout access pipe, or as an overflow orinternal bypass conduit to collect and transfer incoming stormwater thatenters the container and then rises above the surface of the media. Thisvertical pipe is accessible through an opening(s) in the top sidewall 2.A plastic, fiberglass or metal-based fabricated grate or plate 50 mayenclose portions of the top sidewall of the container. An opening 20within the grate would allow the plant's trunk to extend through thegrate and the top sidewall. The grate may be fixed or secured to the topsidewall of the container by way of fastening devices or otherappurtenances.

FIGS. 3(a), 3(b) and 3(c) depicts the first embodiment of the presentinvention which incorporates one or more openings 21, 22, 23, 24 on oneor more sidewalls 10, 11, 12, 13 of the container to service one or moreincoming and/or outgoing pipes 42, 43, 44 of predetermined dimension andlength either straight line or manifold 41 with fittings 45 to receiveand/or discharge stormwater in communication with the container 1 of thepresent invention. These pipes could be accessed through the topsidewall 2 of the container, or through a surface grate or plate 50. Theability to connect piping in a multi-directional configuration allowsfor more flexibility in positioning the stormwater treatment system forboth receiving incoming stormwater and discharging outgoing stormwater.Now referring specifically to FIG. 3(c), this embodiment incorporatesone or more openings 91, 92 on one or more sidewalls of the container 1to allow for the free movement of water that has accumulated above themedia within the container to flow horizontally beyond the exteriorwalls of the container, and thereby further communicate with the media6, and adjoining soil 9, providing a more expansive infiltration area.

Now referring to FIG. 4 of a stormwater management system of the presentinvention, another embodiment of the invention would be that thecontainer would be fabricated in two or more sections with a separatetop slab 60 that would rest on or be affixed to the four sides, 61, 62,63, 64 of the container. Having a separate top slab would allow formaking slight surficial elevational and side-to-side adjustments if siteconditions require such adjustment. A separate top slab would alsolessen the overall lifting weight of the structure at time ofinstallation particularly for large dimension containers.

FIGS. 5a, and 5b depict another embodiment of the present inventionwhich allows for incoming pipes from deeper elevations to enter thecontainer. Often times, due to the location and elevation of upgradientcatch basins or other facilities that collect stormwater for dischargeto a stormwater management system such as the present invention, thepoint of entry to the container must be several feet below surfacegrade. Such factors as existing site conditions, drainage layout plans,and natural or artificial slopes, stormwater conveyance pipes musttraverse a subject site at elevations several feet below ground surface70. In this embodiment one or more incoming pipes 71 would enter thecontainer at a depth below ground surface. Incoming water woulddischarge into a closed bottomed four-sided chamber 72 which ismonolithic or attached to the container and would be composed ofconcrete, metal, or a plastic material. As the water rises within thischamber, it would flow over the interior top sidewall 73 of the chamber,and/or flow through one or more pipes 74 that have been cast in, or areotherwise traversing through the interior sidewall of the chamber. Thewater would then flow onto the media 6 within the container, andinfiltrate through the media, as detailed in the present invention ofFIGS. 1 & 2.

FIG. 6 depicts another embodiment which illustrates a particular pipingschematic of the present invention as a stormwater management systemthat accepts incoming water from an underground pipe emanating fromeither a building's roof, or an upgradient source or location such as anunderground pipe, catch basin, and/or other stormwater receivingreceptor. Water enters the container from an inlet pipe 80 situated on aprimarily horizontal plane. Water passing over one or more openings 81located on the inlet pipe, would have the ability to flow through theopenings and make contact with the surface of the media 6 within thecontainer. Water which is not able to flow through the aforementionedopenings, would continue to flow through the pipe before connecting witha separate underdrain pipe 82 with a plurality of openings that iscollecting infiltrating water flow. Both flows would then combine andcontinue on a primarily horizontal plane and then exit through one ormore sides of the container. An embodiment would be that a verticalriser pipe 83 with an open or closed top 84 may be connected to thehorizontal underdrain pipe. The purpose of this pipe would be to collectexcess water that rises above the surface of the media within thecontainer for evacuation through the underdrain pipe, or another outletpoint; and/or to serve as a cleanout port to be accessed through anopening in the top 85 of the container or through an associated grate,plate or other removable fixture 86.

FIGS. 7a and 7b depicts still another embodiment with similarconfiguration to previous figures represented of the present invention.In this embodiment, a flexible impervious or semi-impervious subsurfacemembrane liner 55 surrounds a substantial portion of the container 1.The purpose of this liner would be to provide a barrier between thecontainer and media 6 associated with the container, and that of nativeor adjoining soils 56. Inlet and outlet piping of various diameter wouldbe able to penetrate and otherwise traverse the wall of the liner. Suchcircumstances which may include this embodiment would be if thestormwater management system of the present invention was locatedproximal to identified sensitive environmental receptors which requireprotection or segregation. Such examples of these receptors could bewater bodies 57, wetlands, drinking water protection areas and otherexamples. Another circumstance where the embodiment of a liner and/orbarrier would be beneficial would be if contaminated soil or groundwaterwas present proximal to the stormwater management system, wherebyinfiltrating water associated with the stormwater management systemcould potentially comingle with or otherwise make contact withcontaminated soil or groundwater thereby spreading the contaminationfurther. The use of a flexible liner would also allow for the expansionof the collection and treatment area beyond the “foot print” of thecontainer, and therefore not be constrained by the dimensions of thecontainer, allowing for the maximization of the infiltrating media area.The flexible impervious or semi-impervious subsurface membrane liner isenvisioned to be composed of rubber, polyethylene, or other material(s)either unique or in composite and typically designed to be a barrier toseparate one physical area from another physical area.

Several of the embodiments of the invention may be connected to a sumppump. A sump pump is a pump used to remove water that has accumulated ina water collecting sump basin, commonly found in the basement of homes.The water may enter via the perimeter drains of a basement waterproofingsystem, funneling into the basin or because of rain or natural groundwater, if the basement is below the water table level. Sump pumps areused where basement flooding happens regularly and to solve dampnesswhere the water table is above the foundation of a home. Sump pumps sendwater away from a house to any place where it is no longer problematic,such as the stormwater treatment system of the present invention.

There are generally two types of sump pumps—pedestal and submersible. Inthe case of the pedestal pump, the motor is mounted above the sump—whereit is more easily serviced, but is also more conspicuous. The pumpimpeller is driven by a long, vertical extension shaft and the impelleris in a scroll housing in the base of the pump. The submersible pump, onthe other hand, is entirely mounted inside the sump, and is speciallysealed to prevent electrical short circuits. There is debate about whichvariety of sump pump is better. Pedestal sump pumps usually last longer(25 to 30 years) if they are installed properly and kept free of debris.They are less expensive and easier to remove. Submersible pumps willonly last 5 to 15 years. They are more expensive to purchase but cantake up debris without clogging.

Sump pump systems are also utilized in industrial and commercialapplications to control water table-related problems in surface soil. Anartesian aquifer or periodic high water table situation can cause theground to become unstable due to water saturation. As long as the pumpfunctions, the surface soil will remain stable. These sumps aretypically ten feet in depth or more; lined with corrugated metal pipethat contains perforations or drain holes throughout. They may includeelectronic control systems with visual and audible alarms and areusually covered to prevent debris and animals from falling in.

The foregoing descriptions and drawings should be assumed asillustrative only of the principles of the invention. The invention maybe configured in a variety of shapes and sizes and is not limited by theaforementioned dimensions, construction and operation of the identifiedparts, materials or embodiments. It is understood that numerousmodifications, changes, and substitutions of the invention will readilyoccur to those skilled in the art and may be resorted to falling withinthe scope and spirit of the invention.

While the previous description contains many specifics, these should notbe construed as limitations on the scope of the invention, but asexemplifications of the presently preferred embodiments thereof. Thusthe scope of the invention should be determined by the appended claimsand their legal equivalents. It is not desired to be limited to theexact details of construction shown and described for obviousmodifications will occur to a person skilled in the art, withoutdeparting from the spirit and scope of the appended claims.

I claim:
 1. A stormwater treatment system with bioretentionfunctionality comprising at least four substantially open verticalsidewalls and a partial horizontal top sidewall affixed to one or moreof said sidewalls, wherein when said system is partially buried in theground, said partial horizontal top sidewall exposes the interior of thesystem to the atmosphere; wherein said system contains discrete layersof organic and inorganic or a mixture of organic and inorganic material;further wherein when said system is partially buried in the ground, saidsystem abuts a street, sidewalk, raised elevation, parking lot, parkinggarage or other open public area; provided said system does not have abottom wall.
 2. The stormwater treatment system according to claim 1,further comprising one or more openings in one or more of the sidewallsof said system, wherein said openings are open to the atmosphere andallow for the ingress and egress of stormwater into and out of saidsystem.
 3. The stormwater treatment system according to claim 2, whereinsaid system is fabricated from an impermeable material selected from thegroup consisting of concrete, metal, fiberglass, plastic or anycombination thereof.
 4. The stormwater treatment system according toclaim 1, further comprising a grate or plate, wherein said plate orgrate encloses the opening of the partial horizontal top sidewall andcontains an opening wherein said opening allows vegetation planted inthe interior of said system to grow upward from the system through saidopening in said plate or grate.
 5. The stormwater treatment systemaccording to claim 4, wherein said grate or plate is fabricated fromplastic, fiberglass, metal or any combination thereof.
 6. The stormwatertreatment system according to claim 1, further comprising one or moreopenings in one or more side walls of said system and one or more excesswater drainage pipes in contact with said openings wherein said pipesallow accumulating stormwater to enter and thereafter exit said systemto a designated location.
 7. The stormwater treatment system accordingto claim 6, wherein said excess water drainage pipes are straight lineor manifold pipes or a combination thereof.
 8. The stormwater treatmentsystem according to claim 7, further comprising fittings to secure saidexcess water drainage pipes to said openings wherein said fittings areselected from the group consisting of screws, bolts, clips, bars,clasps, clamps, and/or couplings.
 9. The stormwater treatment systemaccording to claim 6, wherein said excess water drainage pipes directexcess stormwater accumulating above the filtering layers to exit thesystem horizontally out of the system through the openings in saidsidewalls.
 10. The stormwater treatment system according to claim 1,further comprising one or more incoming water pipes and a closed bottomfour-sided chamber wherein when said incoming pipe or pipes are situatedwithin the interior of said system below the surface of the ground inwhich the system is installed; wherein said incoming pipes are situatedso that excess stormwater accumulating in said system is directed tosaid chamber by said incoming pipe or pipes.
 11. The stormwatertreatment system according to claim 10, wherein said closed bottomfour-sided chamber is attached to said system and is fabricated out ofconcrete, metal, fiberglass, plastic or a combination thereof.
 12. Thestormwater treatment system according to claim 10, wherein said closedbottom four-sided chamber further comprises one or more pipes with orwithout pipe fittings that traverse a wall of said chamber.
 13. Thestormwater treatment system according to claim 12, wherein said pipes,and/or pipe fittings are precast into one or more walls of said chamber.14. The stormwater treatment system according to claim 1, wherein saidsystem further comprises a series of pipes in communication with astormwater receiving receptor installed in a building, outdoor publicarea, street, road, sidewalk, parking lot or parking garage.
 15. Thestormwater treatment system according to claim 14, wherein saidstormwater receiving receptor is connected to an underground pipe thatdirects stormwater away from said building, outdoor public area, street,road, sidewalk, parking lot or parking garage.
 16. The stormwatertreatment system according to claim 15, wherein said stormwaterreceiving receptor is a drainage pipe connected to the roof, gutters orbasement of a building and includes a catch basin.
 17. The stormwatertreatment system according to claim 14, further comprising an integratedhorizontal inlet pipe connected to said drainage pipe wherein said inletpipe directs stormwater into the system.
 18. The stormwater treatmentsystem according to claim 17, wherein said integrated horizontal inletpipe contains holes that allows stormwater that has entered into saidintegrated horizontal inlet pipe to flow out of said integratedhorizontal inlet pipe into the surrounding media contained in thesystem.
 19. A stormwater treatment system, with bioretentionfunctionality comprising at least four substantially open verticalsidewalls; a partial horizontal top sidewall affixed to one or more ofsaid open vertical sidewalls; a series of pipes in communication with astormwater receiving receptor installed in a building, outdoor publicarea, street, road, sidewalk, parking lot or parking garage; anintegrated horizontal inlet pipe wherein said inlet pipe directsstormwater into the system further wherein said integrated horizontalinlet pipe contains holes that allows stormwater that has entered intosaid integrated horizontal inlet pipe to flow out of said integratedhorizontal inlet pipe into the surrounding media contained in thesystem; an underdrain pipe connected to said integrated horizontal inletpipe, wherein stormwater that does not flow out of the holes of saidintegrated horizontal inlet pipe flows into said underdrain pipe whereinsaid underdrain pipe contains a plurality of openings and extends fromsaid horizontal inlet pipe to an opening in the sidewall opposite to thelocation of the horizontal inlet pipe, wherein when stormwater enterssaid underdrain pipe from the horizontal inlet pipe, said stormwater isdirected out of the system into the surrounding soil; wherein saidsystem contains discrete layers of organic and inorganic or a mixture oforganic and inorganic material; wherein when said system is partiallyburied in the ground, said partial horizontal top sidewall exposes theinterior of the system to the atmosphere; wherein when said system ispartially buried in the ground, said system abuts a street, sidewalk,raised elevation, parking lot, parking garage or other open public area;provided said system does not have a bottom wall.
 20. The stormwatertreatment system according to claim 19, further comprising a verticalriser pipe connected to said horizontal underdrain pipe, wherein saidvertical riser pipe directs excess stormwater to the horizontalunderdrain pipe which evacuates said stormwater out of the system andinto the soil surrounding the system wherein said vertical riser pipe isused to flush the system of contaminants is accessible through anopening in an associated removable fixture selected from the groupconsisting of a cover, plug, grate or plate.